A. Field of the Invention
The present invention generally relates to temperature control systems and methods, and, more particularly, to a new self-cleaning oven control system and method.
B. Description of the Prior Art
Self-cleaning ovens and temperature controls therefor are well known in the art as exemplified by U.S. Pat. Nos. 4,775,777 and 4,904,849. Conventionally, bake temperature controls for self-cleaning ovens are capable of recalibration and service to compensate for oven components that deviate from design specification or to accommodate individual user preferences. Some temperature control systems for self-cleaning ovens are designed to maintain a constant clean temperature even though the bake temperatures have been recalibrated and offset by a predetermined amount from nominal values. Recalibration of the bake temperatures in known systems necessarily affects the clean temperature.
With the advent of digital electronic microprocessor based control systems for controlling the temperature in self-cleaning ovens, specific operating characteristics are inherent in a particular design of the control system. For example, in a specific electric range commercially made and sold by the assignee of the present invention, the digital electronic microprocessor based closed-loop control circuit for controlling the temperature of a self-cleaning oven of the range provides a much finer or greater level of temperature control resolution in the bake mode than in the clean mode.
Furthermore, the average temperature required to provide cleaning in known self-cleaning ovens is extremely high requiring the use of components, both electrical and mechanical, rated for use in such high temperatures. Further, use of high temperatures requires a significantly longer "cool down" time following the clean mode of operation of the self-cleaning oven.
It is, however, a problem to effect cleaning at lower temperatures than what has previously been implemented. That is, some animal fats, for example, will not vaporize at temperatures less than 770.degree. F. Further, smoke produced during the cleaning mode of operation has always been significant in known systems operating at very high temperatures during the clean mode.
A need, therefore, exists to provide an improved clean mode of operation of a self-cleaning oven using an average temperature significantly lower than known temperatures required for self-cleaning of such ovens.